Which physiological effect is caused by increased pressure during deep diving?

Increased partial pressures of nitrogen is the correct answer because, as a diver descends deeper underwater, the surrounding pressure increases. According to Dalton’s Law, the partial pressure of a gas is directly proportional to its percentage in the mixture and the total pressure. As a result, at greater depths, the proportion of nitrogen in the air we breathe becomes significantly greater due to the higher ambient pressure.

This increase in nitrogen pressure can lead to inert gas narcosis and poses a risk of decompression sickness if the diver does not ascend properly after spending time at depths where nitrogen absorption occurs. Understanding the physiological effects of pressure on gases is crucial for safe deep diving practices, especially when planning dives that exceed certain depths or involve prolonged exposure to pressure changes.

In contrast, dehydration and hypothermia are primarily related to environmental conditions rather than the direct impact of increased pressure on gas absorption. Oxygen toxicity is also an important consideration but typically occurs at high partial pressures of oxygen, which is not directly relevant to the physiological effects stemming from nitrogen at standard air mixture levels during deep dives. Thus, the main physiological effect relating to increased pressure during deep diving is the increased partial pressures of nitrogen.